There are many traditional and newly emerging communications technologies that are addressing the connectivity and communications requirements for person-to-person and machine-person interaction. The physical communications technologies include:
Low bandwidth telephone systems--the regular home and office telephone service; simple data can be sent over these lines with the use of modem technology (currently at 14.4 kbps). Within the traditional telephone network, several high bandwidth means of communications are used to digitally transmit bundles of voice lines. These include: microwave, fiber optic, and satellite communications. PA1 ISDN Services--phone companies are trying to introduce higher bandwidth digital services that can also carry regular voice, but with the extra bandwidth (64 kbytes and higher) can also support digital data communications and potentially low-end video conferencing. PA1 Fiber Optic--cable companies and phone companies want to bring this high bandwidth (mbytes) service to the individual home. This will eventually replace the coaxial cables currently used to deliver cable television services. PA1 Satellite Services--these provide a high bandwidth alternate to fiber optic communications. PA1 Computer networks such as the Internet, LANs, and WANs.
These technologies are all meant to deliver data, analog and digital (but increasingly digital), from point A to point B. If the data can be presented in a real-time fashion then two-way interactive communications can be established. This happens already with voice, which is a low bandwidth signal (under 3 khz). However, with graphics, moving pictures, and video images, the bandwidth requirements are several orders of magnitude higher. Many of the above physical communications technologies are meant to provide sufficient bandwidth not only for voice, but also for video in a real-time fashion (e.g., movies, teleconferencing, video conferencing).
The basic problem with any real-time graphics or video images, is that moderate to high bandwidth continuously connected services are required. This means coaxial cables, fiber optics, and in some limited cases (degraded video images) ISDN services are required. The continuous connection requirement means that real-time graphics or video interaction (video conferencing) cannot be accomplished over the Internet and LANs that are packet switched (bursty, message oriented so there is no guarantee of continuous service).